The photocoloration and the discoloration of organic titanium complexes were investigated. The organic titanium complexes of alkyltitanates with hydroxy -carboxylic acids such as citric, tartaric, malic or lactic acids were colored by irradiating with U.V. ray. The color after irradiation varied in the different organic titanium complexes when they were solid-state, and also varied in different solvents when they were solution-state. It was concluded that the formation of the colored products was due to the photoreduction from Ti (IV) to Ti (III). On the other hand, the color produced by U.V. ray disappeared when the colored products were allowed to stand in the dark. Oxygen played a dominant role in the discoloration.